1. Field of the Invention
The present invention relates to a scintillator panel and a radiation image sensor which are used for medical X-ray photography and the like, and methods of making them.
2. Related Background Art
While X-ray sensitive films have been used in medical and industrial X-ray photography, radiation imaging systems using radiation detectors have been coming into wider use from the viewpoint of convenience and their storability of photographed results. In such a radiation imaging system, pixel data caused by two-dimensional radiation are acquired by a radiation detector as an electric signal, which is then processed by a processing unit, so as to be displayed onto a monitor.
Conventionally known as a typical radiation detector is one disclosed in WO 92/06476 or the like. In this radiation detector, a scintillator directly formed on a substrate and an imaging device are bonded together, such that the radiation incident from the substrate side is converted into visible light by the scintillator, so as to be detected.
On the other hand, Japanese Patent Application Laid-Open No. HEI 5-196742 and No. SHO 63-215987 disclose a radiation detector in which, in order to protect a scintillator formed on an imaging device or a fiber optical plate (FOP), i.e., an optical part constituted by a plurality of fibers bundled together, against vapor (moisture) in the air, a water-impermeable, moisture-resistant barrier is formed on the upper side of scintillator layer.
In the case where the scintillator is directly formed on the substrate as in the radiation detectors mentioned above, however, the state of substrate surface (such as unevenness, roughness, and streaks formed upon rolling) has greatly influenced characteristics of scintillator panels. Namely, optical mirror surfaces are hard to prepare in Al sheets, Be sheets, and the like which are used as substrates. Therefore, in the case where radiation is made incident from the substrate side and is converted by the scintillator into visible light, from which an image is subsequently acquired through lens coupling and the like, image quality, luminance, resolution, and the like have greatly been influenced by the state of substrate surface.
It is an object of the present invention to provide a scintillator panel, a radiation image sensor, and methods of making them, which would not be influenced by the state of substrate surface.
The scintillator panel of the present invention comprises a radiation-transparent substrate, a flat resin film formed on the substrate, a reflecting film formed on the flat resin film, and a scintillator formed on the reflecting film.
According to the scintillator panel of the present invention, since the scintillator is provided on the flat resin film formed on the substrate, characteristics of the scintillator panel can be kept from changing due to the state of substrate surface. Also, the scintillator plate can enhance its optical output since it has a reflecting film.
The scintillator panel of the present invention is characterized in that at least a part of the scintillator of scintillator panel is covered with a transparent organic film. Since the scintillator is covered with the organic film, the scintillator panel of the present invention can protect the scintillator against vapor (moisture).
The radiation image sensor of the present invention comprises a radiation-transparent substrate, a flat resin film formed on the substrate, a reflecting film formed on the flat resin film, a scintillator formed on the reflecting film, and an imaging device disposed so as to face the scintillator. According to the radiation image sensor of the present invention, since the scintillator is provided on the flat resin film formed on the substrate, characteristics of the scintillator panel comprising the radiation image sensor can be kept from changing due to the state of substrate surface. Also, the scintillator plate can enhance its optical output since the reflecting film is provided.
The radiation image sensor of the present invention is characterized in that at least a part of the scintillator of radiation image sensor is covered with a transparent organic film. According to the scintillator of the present invention, since the scintillator is covered with the organic film, the scintillator can be protected against vapor (moisture).
The method of making a scintillator panel in accordance with the present invention comprises steps of forming a flat resin film on a radiation-transparent substrate, forming a reflecting film on the flat resin film, and forming a scintillator on the reflecting film.
In the method of making a scintillator panel in accordance with the present invention, the flat resin film is formed on the substrate, and the scintillator is formed on the flat resin film, whereby a scintillator panel whose characteristics would not change due to the state of substrate surface can be made. Also, since the reflecting film is formed on the flat resin film, the optical output of scintillator plate can be enhanced.
The method of making a scintillator panel in accordance with the present invention may further comprise a step of covering at least a part of the scintillator with a transparent organic film. Since the scintillator is covered with the organic film, the present invention can make a scintillator panel which can protect the scintillator against vapor (moisture).
The method of making a radiation image sensor of the present invention comprises steps of forming a flat resin film on a radiation-transparent substrate, forming a reflecting film on the flat resin film, forming a scintillator on the reflecting film, and disposing an imaging device opposite the scintillator.
In the method of making a radiation image sensor in accordance with the present invention, the flat resin film is formed on the substrate, and the scintillator is formed on the flat resin film, whereby a radiation image sensor comprising a scintillator panel whose characteristics would not change due to the state of substrate surface can be made. Also, since the reflecting film is formed on the flat resin film, it is possible to make a radiation image sensor which can enhance the optical output of scintillator plate.
The method of making a radiation image sensor in accordance with the present invention may further comprises a step of covering the scintillator with a transparent organic film. Since at least a part of the scintillator is covered with the organic film, the present invention can make a radiation image sensor comprising a scintillator panel which can protect the scintillator against vapor (moisture).
The transparent organic film may cover the all surfaces (top and side surfaces) of the scintillator for securely protecting the scintillator against vapor. More preferably, the transparent organic film may reach to the surface of the substrate.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.